You can use CloudLinux Selector to enable the Mailparse extension in PHP via Plesk.

1. Log in to your Plesk account.

2. In the right-hand sidebar, click on PHP Selector.

3. Click on the Extensions menu.

Note: If the Extensions page shows an error related to the native PHP version, change it to a non-native version first.

4. Checkmark Mailparse. Once enabled, it will display a success message.

The message will read that the module Mailparse is saved.